pontoon building advice

[fspitzer]

Hi All,
Just registered to the site. Very cool. I am totally green to boat building but a very capable builder/woodworker. I am interested in building a small pontoon boat for the kids and I to putt around on the small lakes and slow rivers in our area (eastern panhandle wv), I like the stability of this kind of craft with kids. This is my idea for the pontoons, and please feel free to call me an idiot or say I'm on to something or give me a better way. I'm thinking of using sonotubes filled with those pool "noodles", forming a nose of foam and then fiberglassing the whole thing. The noodles have tremendous flotation ability and are cheap. I would like to build the boat approx 6.5 ft.x
12ft. The sonotube are about 2.50 a ft. and can be ordered 12 ft. To strengthen the tubes I would cut 3/4 inch plywood disks glued and tacked in place every 3-4ft. Just a thought that appeared in my frugal mind. OR would it be better/easier to build wooden pontoons. Any response would be appreciated.
Frank

 

[tashasdaddy]

Re: pontoon building advice

the noodle will not add any floatation. the idea of floatation in a boat is to keep it from completely sinking, when holed. not to make it float better. pontoons are basically balloons, but not under pressure. the volume of air is the floatation.

 

[vwfoolwhy]

Re: pontoon building advice

I've actually seen the sonatubes used on a floating dock with a slide.

It was built the same way you described but with out the noodles.

It was constructed out of four 4' tubes sealed at the ends with 3/4 ply and glassed over. It's been in use every year for the fast 5 years. So it has held up with out any leaks that I know of.

If you have the time and green backs then go for it.

You might start a new DYI build kit

Mike Methuen, MA

 

[CATransplant]

Re: pontoon building advice

How much does a 12' sonotube in the size you're using weigh? I'm not worried about flotation...just the weight of the structure you'll be building.

 

[fspitzer]

Re: pontoon building advice

Thanks all for responding. Tashadaddy, thanks for setting me straight on the flotation issue, I guess I need to calculate how big the pontoon needs to be per calculated weight of the boat to gat the correct volume of air. Any help with a formula would be appreciated.
vwfoolwhy, thanks for the example, sounds similiar to what I want to do. Thanks also for the buisness idea but it will be a big accomplishment to get one boat built for myself.
CATransplant, I went to the website for sonotube but couldnt find a weight chart for the tubes, but estimating the weight of a four ft. x 16 inch tube at Home Depot at 7-10 pounds. I'm guessing a 12ft. tube to weigh 25 pounds. Would seem to me by the time I add my bracing inside and fiberglass it would weigh similiar to a wooden pontoon. Thoughts?
Thanks
Frank

 

[mtchess]

Re: pontoon building advice

I just found this post and see that their have been no other replies.
What you have to do is determin the volume in gallons of the tube you will be using. This will tell you how much weight it will support. Water weights 8.3 lbs per gallon. So if you had a tube that had a volume of one gallon it will have a bouncy of 8.3 lbs

 

[jonesg]

Re: pontoon building advice

Just go look at some pontoon boats at the marine stores.
I've built floats from sheeted foam (heavy) and from formers and wood sheet, glassed with cloth and access holes on top w/ panel.
You can get plans online, its similar to building a boat, lay down a keel and install formers, stringers and then sheet.

shucks, you could do better than this one w/ 2 canoes
http://www.jemwatercraft.com/pontoon.php

redneck riviera
http://www.glen-l.com/designs/house/huckfinn.html

 

[Dunaruna]

Re: pontoon building advice

Frank, there is a pi calculation but my little brain is getting too old to remember it. When i built my toons, I used a guide similar to this one (these weights refer to both toons half submerged) -

My toons -

 

[Bamby]

Re: pontoon building advice

Why not find a old decrepid pontoon boat you can buy cheap. They are out there for a song if you have time on your side. Then this winter you can modify it to suit your needs. Love to have toons on above post can see a houseboat on them.
Gregg

 

[Mark42]

Re: pontoon building advice

How about stopping at a plumbing supply store and see what is available in PVC or ABS pipes in the 20" size?

 

[Silvertip]

Re: pontoon building advice

I will look through my archieves for a site that had reject or scratched/dented pontoons for sale (just the tubes). Seems to me if time is a constraint, this would be the way to go.

 

[quantico]

Re: pontoon building advice

Yikes, I would suggest buying an older dead pontoon boat is a much better use of your time and will yield a better end result. I also can tell you if you plan on going at any speed faster than a trolling motor that the real pontoons are a lot stronger than what you are describing. The pontoon has to maintain it;s shape with better than a thousand pounds pressing on the bottom. What you would build would have to be strong enough to survive that level of force.

I know of so many people around me ( and myself ) that have purchased 500 dollar pontoon boats from 21 - 24 feet and then re-decked and re-wired and found a good used engine. Your wood woodworking skills could be very helpful in building a steering console or a couple bench seats.

I have one neighbor with a 12 - 14 foot pontoon boat and he usually goes out with his dog and two people tops.... he has problems keeping the boat balanced well because of the short length and narrow design. I highly suggest at least a 18 foor used boat, but many 21 - 24 footers are available for 500 dollars or so... I would suggest you find a very used pontoon and start with a better platform.